Low pollution reciprocating heat engine

ABSTRACT

This disclosure relates to a heat engine which operates generally on the basis of the Carnot cycle and includes the usual cylinders, pistons and crankshaft. However, the cylinders of the engine are arranged in pairs with each pair including a large cylinder and a small cylinder. Heated gas enters the large cylinder to perform work and then flows through cooling means to the small cylinder wherein reversible adiabatic compression takes place and the compressed gases are returned to a heater for recycling.

United States Patent Barrett Feb. 25, 1975 LOW POLLUTION RECIPROCATING HEAT OTHER PUBLICATIONS ENGINE Power En ineerin ,Januar I958, 72-74, Vol. I, [76] Inventor: George M. Barrett, R.R. No. 5, NO 6 g g y pp G 11,0 t d a n ano Cam 3 Phys1cs by E. Hausmann and E. Slack, D. Van Nos- Flledz p 5, 1972 trand (30.; New York, 3rd ed., 1948, pp. 309-311.

[21] Appl. No.: 286,351

Primary Examiner-Martin P. Schwadron Apphcauon Data Assistant ExaminerAllen M. Ostrager [63] Contmuation-m-part of Ser. No. 86,738, Nov. 4, Attorney, Agemvor Fi ])i|1 Brown, R ik &

1970, Pat, No. 3,698,184, and a continuation-in-part Wight of Ser. No. 261,232, June 9, 1972.

[52] U.S. Cl. 60/682 [57] ABSTRACT [5]] Int. Cl. F01k 25/00 This disclosure rel-ates to a heat en gme whrch operates [58] Field of Search ..6(l/682 generally on the basis of the Camot Cycle and includes the usual cylinders, pistons and crankshaft. However, [56] References C'ted the cylinders of the engine are arranged in pairs with UNITED STATES PATENTS each pair including a large cylinder and a small cylin- 2,47l,476 5/1949 Benning et al 60/36 der. Heated gas enters the large cylinder to perform 3,180,078 4/1965 Liston 60/24 X work and then flows through cooling means to the 364579722 7/1969 Bush 1 60/24 small cylinder wherein reversible adiabatic c0mpres 3,724,206 4 1973 Ross 60/24 Sion takes place and the compressed gases are 3,772,883 11/1973 Davoud et al. 60/36 X turned to a heater for recycling FOREIGN PATENTS OR APPLICATIONS 8 Cl 3 D F 643,598 9 1950 Great Britain 60/24 gums HEATER Q U E L 5U 52 SUPPLY 3| 8 28 3 4n V LOW POLLUTION RECIPROCATING HEAT ENGINE This application is an improvement over and a continuation-in-part of my copending applications Ser. No. 86,738 entitled Low Pollution Heat Engine filed Nov. 4, I970, now US. Pat. No. 3,698,184, granted Oct. l7, I972, and Ser. No. 261,232, entitled Heat Engine, filed June 9, 1972.

This invention relates in general to new and useful improvements in reciprocating engines, and more particularly to a novel reciprocating engine which operates generally in accordance with the Carnot cycle.

BACKGROUND OF THE INVENTION It is well known to convert heat energy into mechanical energy in an engine having a gas sealed therein. In accordance with the well known Carnot cycle, by selectively heating and cooling gas within a closed system which includes at least one movable wall, that wall can be made to reciprocate. By connecting the wall to a crankshaft, the reciprocable movement of the wall (piston) is converted into rotary movement to form an engine.

It is also well known that certain hydrocarbon gases,

including propanes, butane, may advantageously be utilized in a fuel with substantially complete combustion resulting wherein the exhaust gases therefrom constitute only minor pollutants as compared to other fuels customarily utilized in conjunction with an internal combustion engine.

SUMMARY OF THE INVENTION In accordance with this invention, it is proposed to utilize the advantageous features of the Carnot cycle in a reciprocating engine with the mechanically compressed gases being by-passed from the engine through a heater utilizing one of the preferred hydrocarbon gases as a fuel, and returning the heated gas to the engine in a cylinder thereof where isothermal expansion and reversible adiabatic expansion occurs, and therein utilize the expansion characteristics of the heated gas to produce work to effect rotation of a crankshaft.

It is also proposed to accelerate the isothermal compression of the gas within the closed system of the engine by incorporating therein cooling means.

Cooling means, in accordance with the foregoing, may be merely an internal passage within an engine component which is water cooled, or may be external, and the external cooling means can be part of a combined heater and air conditioning system if it is so desired.

It is further proposed in accordance with this invention to utilize the same gas fuel supply for operating the heater and for replenishing the gas within the engine, certain hydrocarbon gases being suitable for use not only as a fuel, but also the gas within the engine whereby a single gas supply is required to take care of all operating conditions of the engine.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings:

IN THE DRAWING FIG. I is a schematic view of a heat engine construction in accordance with this invention. FIG. 2 is a fragmentary schematic view of the heat engine with a modified form of cooling system.

FIG. 3 is a fragmentary schematic view showing a further type of cooling means.

Reference is now made to FIG. I where there is illustrated a modified form of reciprocating engine which is generally identified by the numeral 10. The engine includes an engine block 11, which block for simplicity purposes, has been illustrated as including four cylinders. However, it is to be understood that the number of cyliinders may vary although the cylinders must be provided in pairs as will be obvious hereinafter.

The engine 10 also includes a crankshaft 12 which is suitably mounted within the engine block 11 for rotation. The'cylinder has formed therein a relatively large cylinder 13 with a piston 14 which is connected to the crankshaft 12 by means of a connecting rod 15.

The engine 10 next includes a smaller diameter cylinder 16 having mounted therein a piston 17 which is connected by means of a connecting rod 18 to the crankshaft 12.

If necessary, the engine 10 could be restricted to cyclinders l3 and 16. However, in order to provide for a balanced engine condition, the engine 10 is illustrated as also including a large cylinder 20 having mounted therein a piston 21 connected to the crankshaft 12 by means of a connnecting rod 22. Associated with the cylinder 20 is a small cylinder 23 having a piston 24 therein connected by a connecting rod 25 to the crankshaft I2.

The engine 10 also includes a head 26 having suitable valves 27 therein which will be of a conventional type and will not be described hereinafter. The head 26 has associated with one valve of the cylinder 13 a supply passage 28 which is connected through a throttle valve 30 to a supply line 31 leading from a heater 32. The head 26 has a similar intake or supply passage 33 associated with the cylinder 21 and connected to the throttle valve 30.

The cylinder 16 is coupled to the cylinder 13 by means of a supply passage 34 which in the illustrated form of the invention passes through a water jacketed area of the head 26 for effecting the cooling of gases passing therethrough. In a like manner, the cylinder 23 is coupled with the cylinder 20 by means of a flow passage 35 which is also water cooled by water circulating through the head 26.

Suitable discharge passages 36,37 lead from the cylinders 16,23 and are connected to a return line 38 leading to the heater 32. The return line 30 has a check valve 40 incorporated therein.

The engine 10 further includes a camshaft 4] for actuating the valves 27 in timed relation, the camshaft 41 being driven from the crankshaft 12 by means of the usual timing sprockets 42,43 and a timing chain 44.

It is to be understood that the engine 10 is of the two cycle type and, accordingly, the camshaft 41 will be driven at the same rotational speed as the crankshaft 12.

The engine 10 may also include a suitable heat exchanger in the form of a radiator 45 which has water flow hoses 46 and 47 coupled thereto, the hoses 46,47 leading to the block 11 and head 26. The crankshaft 12 may also be provided with a suitable fan 48.

In order that the engine 10 may operate, there is provided a gaseous fuel supply 50 having a line 51, provided with a valve 52 for resupplying gas to the closed system of the engine. The gaseous fuel supply 50 is also coupled by means of a line 53 having a valve 54 therein, to the heater 32 for supplying fuel thereto.

OPERATION The gas is heated to a high temperature within the heater 32 and as permitted by the throttle valve TV, the heated gas is admitted into the cylinder through the supply passage 33, forcing piston 21 down. The movement of the piston 21 is due to both isothermal expansion and reversible adiabatic expansion ofthe gases received fromm the heater 32. The piston 21 moves down to the bottom of its stroke with piston 24 moving upwardly towards the top of its stroke. As the crankshaft l2 continues to rotate, the piston 21 moves upwardly, urging the expanded gases out of the cylinder 20 through the flow passage into the cylinder 23 which now has the piston 24 at the top of its stroke, As the expanded gases pass through the flow means 35, they are cooled and by way of isothermal compression, their volume is reduced. It is preferred that the volume of the cylinder 23 corresponds to the volume of the cylinder 20 as reduced by the isothermal compression of the gases so that in effect, no true work is required to move the expanded gases from within the cylinder 20 into the smaller cylinder 24.

As the crankshaft l2 continues to rotate, the cylinder 24 will move upwardly causing reversible adiabatic compression of the gases and forcing the gases out through exhaust passage 37 into return line 38 and through check valve 40 into the heater 32 where they will again be heated and recirculated.

It is to be understood that heated gas flow to the cylinder l3 and from the cylinder 13 to the cylinder 16 and then returning to the heater 32 will be the same as that described with respect to the cylinders 20 and 23, but 180 out of phase with respect to the cylinders 20 and 23, respectively.

Inasmuch as the engine 10 utilizes a fuel for operating the heater 32 which is of the low pollutant type, it will be readily apparent that not only has there been developed a low pollution engine, but also one which can be effectively operated with a minimum of modification from existing internal combustion engine constructron.

Reference is now made to FIG. 2 wherein there is illustrated a modified form of head and cooling means. A head 126 having flow passage therein similar to the flow passage of the head 26 is provided. However, the head 126 differs from the head 26 in that flow passages 134 and 135 thereof are provided with external passages 136 and 137, respectively. The return line 38 has coupled thereto in advance of the check valve 40 a recirculating line 138 having a check valve 140 incorporated therein. The line 138 leads certain of the isothermally compressed and adiabatically compressed gases into a condenser 141 which may be a part of a heater. Gases pass from the condenser 140 through a line 141 to an evaporator 142 which may be part of an air conditioning system. The gases, slightly expanded, leave the evaporator 142 through the external passages 136, 137 for return circulation through the cylinders 16, 23.

Reference is now made to FIG. 3 wherein there is illustrated still a further modified form of head construction generally identified by the numeral 226. The head 226 is modified from the head 26 in that gases exhausting from the cylinder 13, for example, pass through a discharge passage 227 to a condenser 228 and from the condenser 228 through a passage 230 to an evaporator 23]. Expanded gases passing out of the evaporator 231 pass into a return line 232 which is coupled to the cylinder 16, for example, for reversible adiabatic compression therein.

It is to be understood that the general function of the engine 10 will be the same with the several types of head constructions although the engine 10 of FIG. 1 may be more efficient, with the engine arrangements of FIGS. 2 and 3 providing for auxiliaries at a very low heat loss.

Although only several preferred embodiments of the reciprocating heat engine have been illustrated and described herein, it is to be understood that minor variations may be made therein without departing from the spirit and scope of the inventon, as defined by the appended claims.

I claim:

1. A heat engine operable generally in accordance with the Carnot cycle, said engine comprising a crankshaft, at least one large cylinder and one small cylinder each having a respective piston therein and connected to said crankshaft in out of phase relation, a closed system for recirculating a gas through said cylinders; said closed system including a heater, a check valve in advance of said heater, first flow means connecting said heater to said large cylinder, said first flow means including a throttle valve and flow controlling valve means of the positively actuated mechanical type, said closed system between said check valve and the interior of said large cylinder to a point during a work stroke of said piston of said large cylinder being means for effecting isothermal expansion of said gas, further work movement of said large cylinder piston being responsive to reversible adiabatic expansion of said gas, second flow means connecting said large cylinder to said small cylinder said second flow means including cooling means for cooling gas flowing from said large cylinder to said small cylinder and flow controlling valve means for effecting isothermal compression of said gas during the compression stroke of said large cylinder piston, and third flow means connecting said small cylinder to said heater, said third flow means including said check valve and providing for reversible adiabatic compression of said gas within said small cylinder during the compression stroke of the piston thereof.

2. The heat engine of claim 1 wherein the effective volume of said small cylinder is substantially equal to the effective volume of said large cylinder reduced by the degree of isothermal compression.

3. The heat engine of claim 1 wherein said engine includes a liquid cooled engine component and said cooling means of said second flow means is a passage within said engine component.

4. The heat engine of claim 1 wherein said cooling means are external of and separate from said cylinders.

5. The heat engine of claim 1 wherein said cooling means are external of and separate from said cylinders, and of the type suitable for changing external fluid temperature.

6. The heat engine of claim 5 wherein said cooling means includes a heat producing condensor.

7. The heat engine of claim 5 wherein said cooling means includes a heat producing condensor and a heat receiving evaporator.

8. The heat engine of claim 1 wherein said heater is of the type utilizing a gaseous fuel of the minimal pollution class. 

1. A heat engine operable generally in accordance with the Carnot cycle, said engine comprising a crankshaft, at least one large cylinder and one small cylinder each having a respective piston therein and connected to said crankshaft in out of phase relation, a closed system for recirculating a gas through said cylinders; said closed system including a heater, a check valve in advance of said heater, first flow means connecting said heater to said large cylinder, said first flow means including a throttle valve and flow controlling valve means of the positively actuated mechanical type, said closed system between said check valve and the interior of said large cylinder to a point during a work stroke of said piston of said large cylinder being means for effecting isothermal expansion of said gas, further work movement of said large cylinder piston being responsive to reversible adiabatic expansion of said gas, second flow means connecting said large cylinder to said small cylinder said second flow means including cooling means for cooling gas flowing from said large cylinder to said small cylinder and flow controlling valve means for effecting isothermal compression of said gas during the compression stroke of said large cylinder piston, and third flow means connecting said small cylinder to said heater, said third flow means including said check valve and providing for reversible adiabatic compression of said gas within said small cylinder during the compression stroke of the piston thereof.
 2. The heat engine of claim 1 wherein the effective volume of said small cylinder is substantially equal to the effective volume of said large cylinder reduced by the degree of isothermal compression.
 3. The heat engine of claim 1 wherein said engine includes a liquid cooled engine component and said cooling means of said second flow means is a passage within said engine component.
 4. The heat engine of claim 1 wherein said cooling means are external of and separate from said cylinders.
 5. The heat engine of claim 1 wherein said cooling means are external of and separate from said cylinders, and of the type suitable for changing external fluid temperature.
 6. The heat engine of claim 5 wherein said cooling means includes a heat producing condensor.
 7. The heat engine of claim 5 wherein said cooling means includes a heat producing condensor and a heat receiving evaporator.
 8. The heat engine of claim 1 wherein said heater is of the type utilizing a gaseous fuel of the minimal pollution class. 